Soluble guanylate cyclase modulators blunt hyperoxia effects on calcium responses of developing human airway smooth muscle

Abstract

Exposure to moderate hyperoxia in prematurity contributes to subsequent airway dysfunction and increases the risk of developing recurrent wheeze and asthma. The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic GMP (cGMP) axis modulates airway tone by regulating airway smooth muscle (ASM) intracellular Ca(2+) ([Ca(2+)]i) and contractility. However, the effects of hyperoxia on this axis in the context of Ca(2+)/contractility are not known. In developing human ASM, we explored the effects of novel drugs that activate sGC independent of NO on alleviating hyperoxia (50% oxygen)-induced enhancement of Ca(2+) responses to bronchoconstrictor agonists. Treatment with BAY 41-2272 (sGC stimulator) and BAY 60-2770 (sGC activator) increased cGMP levels during exposure to 50% O2. Although 50% O2 did not alter sGCα1 or sGCβ1 expression, BAY 60-2770 did increase sGCβ1 expression. BAY 41-2272 and BAY 60-2770 blunted Ca(2+) responses to histamine in cells exposed to 50% O2. The effects of BAY 41-2272 and BAY 60-2770 were reversed by protein kinase G inhibition. These novel data demonstrate that BAY 41-2272 and BAY 60-2770 stimulate production of cGMP and blunt hyperoxia-induced increases in Ca(2+) responses in developing ASM. Accordingly, sGC stimulators/activators may be a useful therapeutic strategy in improving bronchodilation in preterm infants.

Sex Steroids Influence Brain-Derived Neurotropic Factor Secretion From Human Airway Smooth Muscle Cells

“…BDNF is a member of the neurotrophin growth factor family and is extensively distributed in the non-neuronal, peripheral system . Recent studies, including our own, clearly indicate the importance of BDNF in human airway in the context of asthma and other airway diseases (Dagnell et al, 2007;Prakash et al, 2009;Pan et al, 2010;Aravamudan et al, 2012a;Vohra et al, 2013;Sathish et al, 2013a;Prakash and Martin, 2014;Britt et al, 2015;Thompson et al, 2015;Watanabe et al, 2015). Initially, in the endoplasmic reticulum, BDNF is synthesized as a precursor protein (McDonald and Chao, 1995;Robinson et al, 1995;Lessmann and Brigadski, 2009) that is cleaved to produce pro-BDNF which is further sorted into either secretory vesicle.…”

Soluble guanylate cyclase as an alternative target for bronchodilator therapy in asthma

“…1), the utility of using NO to induce bronchodilation in healthy humans may be inherently masked by the continuous NO generation that takes place in normal human airway (19). This endogenous NO is likely to fully activate sGC on its own and thus would mask any potential bronchodilation response to externally provided NO or to NO-releasing compounds (20). In asthmatic lungs, our study suggests that a significant portion of airway sGC actually becomes NO-unresponsive, which would also render administration of NO or NO donors less effective (21,22).…”

“…To probe the mechanism within a similar setting, we performed Transwell coculture experiments with spatially separated NO-generating and sGC-expressing cells, and examined if this would recapitulate the changes in sGC that we observed in the mouse asthmatic lungs or in the NO-exposed human PCLS. We grew two types of NO-generating cells on apical membranes (a mouse macrophage cell line RAW 264.7 or a human bronchial epithelial cell line A549), induced them with cytokines to express iNOS, and then cultured them above monolayers of two types cells that naturally express sGC, a rat fetal lung fibroblast cell line (RFL-6) or primary HASMCs (14,20) (Fig. 4A).…”

Th1 cytokines TNF-α and IFN-γ promote corticosteroid resistance in developing human airway smooth muscle

“…Cell culture. Human fetal ASM cells were isolated from deidentified fetal tracheobronchial tissue (18 -22 wk of gestation) as previously described (10,21). Cells were for in vitro use only and considered exempt by Mayo Institutional Review Board.…”